Rumble strip responsive systems

ABSTRACT

An embodiment of the present invention includes a device to alter transfer characteristics of a road departure warning installation installed on a road to a driver of a vehicle, including a rumble strip sensor to sense input from a rumble strip and an adjustable vehicle component in communication with the rumble strip sensor, the adjustable vehicle component configured to automatically adjust to increase an amount of input from the rumble strip sensed by the driver. Another embodiment of the present invention includes a device to estimate lateral displacement of a vehicle based on the location of a rumble strip installed on a road with respect to the vehicle, the device including a processor configured to receive four signals indicative of contact of a rumble strip with respective associated four tires of the vehicle and to estimate a lateral distance that the vehicle has traveled beyond the detected rumble strip.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application relates to a co-pending U.S. Application under AttorneyDocket No. 032915-0139 by Hiroshi Kawazoe and Hiroshi Tsuda, entitledRumble Strip Responsive Systems filed concurrently herewith, thecontents of which are incorporated herein in their entirety.

BACKGROUND OF THE INVENTION

Vehicle road departure is the cause of about 40% of all trafficfatalities in the United States. Road departures include both a vehicledriving off a road or off the shoulder of the road, and a vehiclecrossing lanes into an oncoming lane on an undivided road. Inattentivedriving and/or driving while drowsy tends to lead to road departures. Inan effort to combat this, transportation authorities have begun to placerumble strips into roads. Rumble strips are bumps or indentations in thesurface of a road such that when a vehicle's tire drives over a rumblestrip, noise and/or vibration is generated to make the driver aware thathe or she is driving off the road. In some cases, it may be desirable toenhance the noise/vibration resulting from simple contact with therumble strip to alert the driver that he or she is driving off the road.Still further, rumble strips of varying locations and varying patternsand shapes are used based on where the rumble strip is located inrespect to the road. For example, a different type of rumble strip maybe utilized to separate oncoming lanes as compared to the type of rumblestrips that are used to line the sides of roads. In this regard, thepresent inventors have determined that there is a way to utilizeinformation which may be obtained from rumble strip sensors to conveyinformation to the driver of the vehicle.

SUMMARY OF THE INVENTION

characteristics of a road departure warning installation installed on aroad to a driver of a vehicle, comprising a rumble strip sensor adaptedto sense input from a rumble strip, and an adjustable vehicle componentin communication with the rumble strip sensor, the adjustable vehiclecomponent being adapted to automatically adjust, in response to inputinto the rumble strip sensor from a rumble strip, to increase an amountof input from the rumble strip sensed by the driver.

In another embodiment of the invention, there is a device adapted tomake a driver of vehicle aware of contact with a road departure warninginstallation installed on a road, comprising, a rumble strip sensoradapted to sense input from a rumble strip, and a vehicle componentcontrol device adapted to change a state of a vehicle component incommunication with the vehicle component control device in response toinput into the rumble strip sensor from a rumble strip.

In another embodiment of the invention, there is a device adapted todetect a road departure warning installation installed on a road thatcomes into contact with a tire of a vehicle comprising a rumble stripsensor adapted to sense input from a rumble strip, wherein the sensorincludes, a vibration sensor in communication with at least one of asprung mass and an unsprung mass, the vibration sensor being adapted todetermine a frequency of vibration of the sprung mass or the unsprungmass and to output a signal indicative of the frequency of vibration ofthe sprung mass or the unsprung mass, and a processor in communicationwith the vibration sensor and adapted to receive the signal, wherein theprocessor is also adapted to analyze the signal and determine whetherthe frequency of vibration is indicative of tire contact with a rumblestrip based on the signal.

In another embodiment of the invention, there is a device adapted toestimate lateral displacement of a vehicle based on the location of aroad departure warning installation installed on a road with respect tothe vehicle, comprising a processor adapted to receive four signalsindicative of contact of a rumble strip with respective associated fourtires of the vehicle, wherein the processor is further adapted toestimate a lateral distance that the vehicle has traveled beyond thedetected rumble strip based on which of the four tires is associatedwith a respective signal.

In another embodiment of the invention, there is a device adapted todetect a road departure warning installation installed on a road thatcomes into contact with a tire of a vehicle comprising a rumble stripsensor adapted to detect the presence of a rumble strip, wherein thesensor includes a displacement sensor adapted to determine a state ofdisplacement of a road surface relative to a location on the vehicle asthe vehicle moves along the road and to output a signal indicative ofthe state of displacement, and a processor in communication with thedisplacement sensor and adapted to receive the signal, wherein theprocessor is also adapted to analyze the signal and determine whetherthe state of displacement of the road surface is indicative of thepresence of a rumble strip based on the signal.

In another embodiment of the invention, there is a device adapted todetermine whether a vehicle is deviating into an oncoming lane of anun-divided highway, comprising a processor adapted to receive at least afirst signal indicative of contact of a rumble strip with a tire of thevehicle, wherein the processor is further adapted to receive a secondsignal indicative of a RADAR return of an oncoming vehicle, theprocessor including logic to determine that the vehicle is deviatinginto an oncoming lane when the processor has received the first signaland the second signal.

In another embodiment of the invention, there is a device adapted toestimate lateral displacement of a vehicle based on the location of aroad departure warning installation installed on a road with respect tothe vehicle, comprising, a processor adapted to receive four signalsindicative of contact of a rumble strip with respective associated fourtires of the vehicle, wherein the processor is further adapted toestimate a direction in which the vehicle is traveling with respect tothe direction of a plurality of detected rumble strips based oninformation contained in the processor regarding a vehicle geometryrelating to the distance between at least one location on the vehicleand at least one of the four tires.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic of an embodiment according to the firstinvention.

FIG. 2 shows the implementation of the first embodiment of the inventioninto a vehicle.

FIG. 3 shows a vibration sensor according to an embodiment of theinvention.

FIG. 4 depicts a vehicle as all four wheels cross a rumble strip.

FIG. 5 a depicts determination of the lateral speed of the vehicle asthe vehicle crosses a rumble strip according to an embodiment of theinvention.

FIG. 5 b depicts determination of the heading of the vehicle as thevehicle crosses a rumble strip according to an embodiment of theinvention.

FIG. 6 depicts graphical representations of the differences in input onconcrete roads and asphalt roads.

FIG. 7 depicts graphical representations of filtering out road inputfrequencies utilizing band-pass filters.

FIG. 8 depicts continuous and intermittent rumble strips.

FIG. 9 depicts departure scenarios on a continuous rumble strip.

FIG. 10 depicts a departure scenario on an intermittent rumble strip.

FIG. 11 depicts time periods pertinent to an embodiment of the inventionin relation to intermittent rumble strips.

FIG. 12 depicts a divided road under construction.

FIG. 13 depicts a rumble strip separating oncoming lanes.

FIG. 14 depicts control of a vehicle component in relation to thedistance from a lane marker to a detected rumble strip.

FIG. 15 provides a block diagram of a device adapted to implement anembodiment according to the present invention.

FIG. 16 is a flow chart for an algorithm to implement an embodiment ofthe present invention relating to determining whether or not a driver istaking corrective action in response to running on rumble strips.

FIG. 17 is a flow chart for an algorithm to detect rumble strips.

FIG. 18 is a flow chart for an algorithm to detect a driver's correctiveaction according to an embodiment of the invention.

FIG. 19 is a flow chart for an algorithm to implement another embodimentof the present invention relating to road departure avoidance utilizingsteering commands.

FIG. 20 is a flow chart for an algorithm to implement brake controlaccording to the present invention.

FIG. 21 is a flow chart for an algorithm to implement pretensioning ofseat belts in response to the detection of rumble strips according tothe present invention.

FIG. 22 is a flow chart for an algorithm to implement vehicle control inresponse to the lateral displacement of the vehicle.

FIG. 23 is a flow chart for an algorithm to estimate lateral speed andangle of deviation with respect to rumble strips according to thepresent invention.

FIG. 24 is a flow chart for an algorithm to determine vehicle deviationinto an oncoming lane according to the present invention.

FIG. 25 is a flow chart for an algorithm to increase vehicle stabilityafter detecting rumble strips according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Rumble Strip InputEnhancement

A first embodiment of the present invention is directed towardsimproving the transfer characteristics of road departure warninginstallation devices, such as a rumble strip, to a driver of a vehicle.That is, by practicing a first embodiment of the present invention, thedriver of a vehicle coming into contact with rumble strips will be awarethat the vehicle is contacting rumble strips during the period ofimproved transfer (e.g., the driver will “feel” more of the input).

FIGS. 1 and 2 show schematic representations of a first embodiment ofthe present invention, which includes a device adapted to improve thetransfer characteristics of a road departure warning installation, suchas a rumble strip, installed on a road, to a driver of a vehicle. FIGS.1 and 2 show a rumble strip sensor 100 which is in communication with anadjustable vehicle component, such as a hydraulic steering systemcontrol valve 110, a steering wheel 120, a vehicle suspension system140, a hydraulic power steering circuit 150, a shock absorber 160 and asuspension spring 170. Specific details of the first embodiment will nowbe discussed.

The rumble strip sensor 100 according to an embodiment of the presentinvention is adapted to sense input from a rumble strip into a tire 102of a vehicle. The rumble strip sensor 100 is of a configuration that cansense input from rumble strips into the tires 102 and also can determinewhether or not the input sensed by the rumble strip sensor 100 isindicative of input from a rumble strip. In some embodiments of thepresent invention, the rumble strip sensor 100 is a self-contained unitthat includes logic to determine whether sensed input is inputindicative of a rumble strip. In other embodiments, the sensor 100simply transfers the sensed input from rumble strip contact to aprocessor. That is, it converts the sensed input from a rumble stripinto a signal that is sent to a processor where the signal is analyzedto determine whether or not the signal generated by the sensor 100 isindicative of input from a rumble strip. In yet other embodiments of thepresent invention, the rumble strip sensor 100 is a sensor that isadapted to only sense input from a rumble strip. That is, the rumblestrip sensor 100 is of a configuration that is responsive only to inputfrom a rumble strip into the tire 102. In yet further embodiments of thepresent invention, rumble strip sensor 100 can be any sensor that is ofa configuration that will sense input from a rumble strip and determinewhether or not that input is indicative of input from a rumble strip.

A first embodiment of the present invention can also include anadjustable vehicle component in communication with the rumble stripsensor 100. The adjustable vehicle component of the first embodiment ofthe present invention can automatically increase an amount of input fromthe rumble strip that is sensed by the driver. That is, by increasingthe amount of input from the rumble strip that is sensed by the driver,the driver might be more likely to recognize that he or she is drivingon the rumble strip and take corrective action.

An example of an adjustable vehicle component is the hydraulic steeringsystem control valve 110. The hydraulic steering system control valve110 may be configured such that a resonant frequency of the controlvalve can be adjusted to increase the amount of input from the rumblestrip sensed by the driver through, for example, the steering wheel.This adjustment in the resonant frequency of the control valve toincrease the amount of input from the rumble strip sensed by the driveroccurs in response to input into the rumble strip sensor 100 from therumble strip.

Another example of an adjustable vehicle component in communication withthe rumble strip sensor 100 according to the present invention includesthe steering wheel 120. The steering wheel 120 can be adapted so thatthe resonant frequency of the steering wheel can be adjusted to increasethe amount of input from the rumble strip sensed by the driver inresponse to input into the rumble strip sensor from a rumble strip. Aswith the hydraulic steering system control valve 110 discussedimmediately above, this embodiment of the invention is directed towardsincreasing the input from the rumble strip that is sensed by the driverthrough his or her hands as the driver holds onto the steering wheel120. In an exemplary embodiment, the adjustable vehicle component isadapted to adjust the resonant frequency so that the vibration from thesteering wheel into the driver's hands is substantially increased whenthe vehicle contacts rumble strips.

Another embodiment of the present invention includes adjustment of theresonant frequency of a body 130 of the vehicle to increase the amountof input from the rumble strip sensed by the driver in response to inputinto the rumble strip sensor from a rumble strip. This embodiment canoperate in a similar manner to the adjustment of the resonant frequencyof the steering wheel except that the resonant frequency of the body 130is adjusted, not just the steering wheel. Thus, the driver can sense anincreased input from the rumble strip through not only the steeringwheel but also through, for example, the seat, the brake and/or the gaspedal, as well as, for example, hearing the entire vehicle shake. Inthis embodiment, the amount of input from the rumble strip sensed by thedriver can be considered to increase as a result of a general overallshaking of the vehicle. That is, for example, the driver may hear theshaking of the vehicle where the shaking of the vehicle body may belouder after the resonant frequency of the body of the vehicle isadjusted.

Another embodiment of the present invention also utilizes an increase inthe amount of input from the rumble strip that is sensed by the driverthrough the steering wheel 120. This can be accomplished by utilizing avibration transfer device that is configured to transfer unsprung massvibration of a vehicle suspension generated by input from the rumblestrips to a hydraulic power steering circuit 150. This hydraulic powersteering circuit 150 is in communication with steering wheel 120 suchthat the vibration that is transferred to the hydraulic power steeringcircuit 150 is further transferred to the steering wheel 120. As withsome of the embodiments discussed above, the driver senses increasedinput from the rumble strips through his or her hands.

In a further variant of the present invention utilizing a steering wheelto transfer an increased amount of input from a rumble strip to thedriver, the steering wheel 120, which is in communication with thecontrol valve 110 having an adjustable resonant frequency, as discussedabove, where the resonant frequency of the control valve is adjusted tosubstantially match an unsprung mass vibration of a vehicle suspensiongenerated by the rumble strips so that hydraulic pulsation of hydraulicfluid in the control valve is increased, thus causing the steering wheelto vibrate and thereby increasing the amount of input from the rumblestrip sensed by the driver. By the term substantially match unsprungmass vibration, it is meant that the resonant frequency of the controlvalve is close enough to the unsprung mass vibration of the vehiclesuspension so that the hydraulic pulsation of hydraulic fluid may besufficiently increased to heightened input from the rumble strips sensedby the driver.

In the further embodiment of the present invention, there is anadjustable vehicle suspension system 140 in communication with a rumblestrip sensor 100. This vehicle suspension system 140 is configured toautomatically adjust itself or to permit automatic adjustment inresponse to input into the rumble strip sensor from a rumble strip sothat the amount of input from the rumble strip sensed by the driver isincreased. The adjustable vehicle suspension system 140 may include ashock absorber 160 (the term shock absorber as used in thisspecification and claims also includes struts) and/or a suspensionspring 170. In embodiments including a shock absorber 160, the dampeningfactor of the shock absorber can be adjusted so that the amount of inputfrom the rumble strip that is sensed by the driver is increased. In somerumble strip encounter scenarios, the dampening factor is increased,while in other scenarios, the dampening factor is decreased to increasethe amount of input from the rumble strips sensed by the driver. Inembodiments where the adjustable vehicle suspension system includes asuspension spring 170, the spring constant of the spring isautomatically adjusted to increase the amount of input from the rumblestrip sensed by the driver. Some rumble strip encounter scenarios mayresult in an increase in the spring constant of the spring 170, whileother rumble strip encounter scenarios may result in a decrease in thespring constant to increase the amount of input from the rumble strip.

It is further noted that other embodiments of the present invention canuse different system components to increase the amount of input from arumble strip that is sensed by the driver. Thus, some embodiments of thepresent invention may be utilized with any such device, component, etc.,that will increase the input from a rumble strip that is sensed by adriver of a vehicle.

Also, it is noted that while the above and below embodiments aresometimes described in terms of a device, in general, for implementingthe present invention (and in terms of sensors and processors, inparticular), the present invention also includes a method and system forimplementing the various embodiments of the invention. For example, thepresent invention also includes a method of and a system for making thedriver aware that a vehicle is contacting rumble strips by adjusting thevehicle suspension system as described above.

Rumble Strip Contact Awareness

Other embodiments of the invention will now be discussed. Theseembodiments differ from the embodiments discussed above in that theabove embodiments enhance input from the rumble strips. In the aboveembodiments, the input felt by the driver is still input generated fromcontact with the rumble strip. That is, energy imparted into the vehiclethrough contact with the rumble strip is felt by the driver in anenhanced form. In the embodiments described below, the vibration that isfelt by the driver is not caused by the energy from the rumble stripsimparted into the vehicle but caused by a release of energy from anothersource (such as a battery).

Such embodiments of the present invention can utilize a vehiclecomponent to make a driver aware that he or she is driving on a rumblestrip not by increasing the input generated from contact with the rumblestrip sensed by the driver, but by providing an indication, such as aflashing light, to the driver that he or she is driving on rumblestrips. An example of this is a device that includes a rumble stripsensor 100 that is adapted to sense input from a rumble strip, thedevice being in communication with a vehicle component control device180 that is adapted to change a state of a vehicle component, such as alight, which is also in communication with the vehicle component controldevice 180 in response to input into the rumble strip sensor 100 from arumble strip. According to this embodiment, a state of a vehiclecomponent, such as, for example, a cabin interior light, is changed by acommand from the vehicle component control device 180. For example, whenthe rumble strip sensor 100 senses input from a rumble strip, thevehicle component control device 180 could turn the light on, or if thelight is already on, turn the light off in response to input into therumble strip sensor from the rumble strip. Other examples according tothis embodiment of the invention include an automatically tighteningdriver's seat belt, a power door window and/or a power door lock that isin communication with the vehicle component control device 180. Inembodiments having one or more of these components, the vehiclecomponent control device 180 can issue a command to automaticallytighten the driver's seat belt, to automatically lower or raise thepowered door window, and/or to automatically lock and/or unlock thepower door lock, respectively, when the rumble strip sensor 100 sensesinput from a rumble strip.

Another example according to this embodiment, includes an aerosoldispenser with a nozzle mounted in the vehicle cabin, where thecomponent control device 180 enables the aerosol spray to emit afragrance. That is, the aerosol spray typically does not emit afragrance, but upon the rumble strip sensor sensing input from a rumblestrip, the vehicle component control device 180 enables the aerosoldispenser to emit the fragrance thus changing the state of the aerosoldispenser. In some embodiments of the invention, this fragrance can havea pungent smell which is known to heighten an awareness of a typicalhuman being. Such an embodiment could be useful in a situation where adrowsy driver who is driving on rumble strips smells the fragrance andbecomes less drowsy, and thus more alert.

Yet another example of this embodiment includes a vibrator as a vehiclecomponent that is activated in response to input into the rumble stripsensor from a rumble strip. The vibrator could be, for example, anelectric vibrator installed into the seat and/or into the steeringwheel/steering column such that when the component vibrates, thevibration is felt by the driver. Thus, in some embodiments of theinvention, this vibrator can be in mechanical communication with asteering wheel, a driver's seat and/or a gas petal such that when it isactivated, it vibrates a respective component.

Rumble Strip Detection

Some embodiments of the present invention also include adevice/method/system for detecting a road departure warninginstallation, such as a rumble strip, that is installed on the road thatcomes into contact with a tire of a vehicle. In the first exampleaccording to such embodiments of the invention, there is a rumble stripsensor that is adapted to sense input from a rumble strip inputted intothe tires of the vehicle. The rumble strip sensor can include avibration sensor that is in communication with a sprung mass and/or anunsprung mass. The vibration sensor can be adapted to determine thefrequency of vibration of the sprung mass and/or the unsprung mass andoutput a signal indicative of the frequency of vibration of the sprungmass or the unsprung mass. That is, when the sprung mass or the unsprungmass vibrates as a result of input from the rumble strips into the tiresof the vehicle, the vibration sensor can detect this vibration andconvert the mechanical vibrational energy into an electronic signal thatcan be analyzed by, for example, a processor (described in greaterdetail below).

An example of the function of a vibration sensor according to thepresent invention will now be described. Input frequencies of rumblestrips may be predetermined and stored on board the vehicle for variousvehicle speeds. For example, if the vehicle is driving at 55 miles perhour, the rumble strip input frequency might be 80 hertz. Thus, thevibration sensor would output a signal indicating that the sensor issensing vibration at 80 hertz. The processor 190, receives this signal,and determines that the vibration sensor is sensing the vibration at 80hertz. The processor then compares this to the predetermined storedvalues of vibrations in for example, a lookup table, that are indicativeof vehicle tire contact with a rumble strip for a given speed. Forexample, at 55 miles per hour, the processor may consider vibrationsbetween 70 hertz and 90 hertz to be indicative of contact with a rumblestrip, but if the processor receives a signal of only 65 hertz, theprocessor may consider this to not be indicative of contact with arumble strip.

A vibration sensor according to the present embodiment may include agravity sensor. In some embodiments of the invention, a gravity sensormay be a device that senses a vertical acceleration and/or a up-downacceleration. In some embodiments, it determines an acceleration (e.g.,m/s², G, etc.) and outputs a voltage in proportion to the determinedacceleration. In yet other embodiments, it may output a signalindicative of the determined acceleration. Still further, otherembodiments of the invention may be practiced with a gravity sensor thatsimply converts a sensed acceleration to a proportional output voltage(e.g., there is no actual value determined for the acceleration). Insome embodiments, and device, method or system that may be used toidentify acceleration may be used to as a gravity sensor.

As touched on above, the rumble strip sensor can also include aprocessor 190 that is in communication with the vibration sensor andadapted to receive the signal from the vibration sensor. The processorcan be of a configuration such that the processor can analyze thisoutputted signal from the vibration sensor and determine whether thefrequency of vibration sensed by the vibration sensor is indicative oftire contact with the rumble strip. That is, the processor can analyzethe signal and determine that the frequency of vibration is of afrequency that is indicative of tire contact with the rumble strip.

In some embodiments of the invention, the processor 190 can be used toanalyze other signals, such as a signal indicative of the state of adampening portion of a shock absorber in the vehicle. A shock absorberon a vehicle has a dampening portion which changes state when a vehicletire receives input from, for example, a rumble strip, a bump in theroad, pothole, etc. The processor 190 can be in communication with ashock absorber assembly of the vehicle and receive a signal from theshock absorber assembly that is indicative of the state of the dampeningportion in the shock absorber. The processor 190 can be adapted toreceive this signal and analyze the signal to determine whether theshock absorber is indeed absorbing shock indicative of contact of avehicle tire with a rumble strip (as opposed to, say, a pothole). Theprocessor may contain a lookup table containing information regardingthe state of a dampening portion of the shock absorber when a tire ofthe vehicle is in contact with a rumble strip, and thus determine thatthe signal from the shock absorber assembly is indicative of the stateof a dampening portion of the shock absorber when there is tire contactwith a rumble strip. Such determination could be vehicle speeddependent, or be speed independent. More detailed embodiments utilizinga shock absorber assembly to determine contact with rumble strips willnow be described.

In some embodiments of the invention that utilize a shock absorberassembly to output a signal indicative of the state of a dampeningportion of the shock absorber, the assembly is adapted to output asignal that is indicative of the pressure within the dampening portion,a change in pressure within the dampening portion, and/or a rate ofchange in the pressure of the dampening portion of the shock absorber.The processor 190 can be adapted to receive and analyze the outputtedsignal and determine whether the outputted pressure, change of pressureand/or the output of rate of change of pressure in the dampening portionof the shock absorber is indicative of tire contact with a rumble stripbased on the signal, again utilizing, for example and not by limitation,a lookup table containing stored ranges. The processor 190 can also bein communication with a wheel assembly of a vehicle that is adapted tooutput a signal indicative of the state of compression in a tire portion220 of the wheel assembly 210. When the tire portion 220 of the wheelassembly 210 comes into contact with a rumble strip, the tire, beingmade out of rubber or a similar elastomeric material, will compress (andthen expand) or vice versa. The wheel assembly 210 can be adapted tooutput a signal that is indicative of the state of compression in thetire portion 220. This signal can be received by the processor 190 andanalyzed by the processor to determine whether the state of compressionin the wheel assembly 210 is indeed indicative of tire contact with arumble strip. In one example of this embodiment, the wheel assembly 210can be configured to output a signal that is indicative of pressure, achange in pressure, and/or rate of change in pressure in the tire 220.The processor 190 can receive this signal and analyze the signal todetermine whether the pressure, change in pressure, and/or the rate ofchange in pressure of the tire portion is indicative of contact of thetire portion with a rumble strip. In other embodiments of the presentinvention, a strain gauge, for example, can be attached to the tireportion of the wheel assembly 210 to determine a change in strain, or arate of change of strain in the tire portion 220 of the wheel assembly210. The wheel assembly 210 may also be configured to output a signalindicative of the state of rotation of at least a portion of the wheelassembly, which can include, for example, the tire portion 220 and/orthe hub of the wheel assembly and/or an axle of the wheel assembly. Theprocessor 190 can receive this outputted signal and analyze the signalto determine whether a change of state of rotation of this portion ofthe wheel assembly is indicative of contact of the tire with a rumblestrip. The wheel assembly 210, according to this embodiment, can beadapted to output a signal that is indicative of the rotation speed, thechange in rotation speed, and/or a rate of change of rotation speed ofthe rotating portion of the wheel assembly, the processor 190 beingadapted to analyze the signal and determine whether the outputted signalcontains data indicative of tire contact with a rumble strip. By way ofexample and not by way of limitation, if the processor 190, afteranalyzing the signal, determines that the rotation speed of the rotatingportion is increasing by 5 revolutions per second and then decreasing by5 revolutions per second, the processor may determine, based on thevehicle speed, that this change in rotation of the rotating portion ofthe wheel assembly is indicative of contact with rumble strips. By wayof further example and not by way of limitation, a wheel speed sensormay be used to determine that the vehicle is contacting a rumble strip.In an exemplary embodiment, a wheel speed sensor may be composed of arotor with projections, much like a gear, and a magnetic pickup. Thesensor outputs pulses when the projections pass by the magnetic pickup.A processor may analyze the pulses and determine a wheel rotation speedby a frequency of the pulse input. For example, at about 60 kph, thefrequency may be about 400 Hz. When a tire contacts rumble strips, thetire may vibrate in the direction of the tire rotation. Consequently, alower frequency of the pulse is added to the based frequency thatindicates wheel rotation speed. For example, at about 60 kph, thefrequency may be about 450 Hz. Thus, the change in the frequency ofdetection may be utilized to determine that the vehicle is contactingrumble strips.

Another embodiment of the invention includes a device that can detectcontact with a road departure warning installation such as a rumblestrip, installed on a road, with a tire of the vehicle by utilizing amicrophone 230 that is adapted to output a signal indicative of thesound sensed by the microphone. The microphone can be placed in alocation on the vehicle where the sound generated by the rumble stripcontacting the tire can be sensed and the microphone then outputs asignal indicative of this sensed sound. The microphone 230 can be incommunication with the processor 190, and the processor can be adaptedto receive the outputted signal from the microphone 230. The processorcan also be adapted to analyze the outputted signal from the microphone230 and determine whether the sound sensed by the microphone isindicative of a sound that is created by tire contact with a rumblestrip based on the signal outputted from the microphone 230.

In another example of an embodiment of the invention used to detectcontact with rumble strips, there is a device that detects a rumblestrip that includes a sensor adapted to sense input from the rumblestrip, where the sensor includes a displacement sensor 240 thatcomprises a sprung mass 242, as shown in FIG. 3. The displacement sensoris configured to determine a state of displacement of the sprung masswhen the sprung mass is displaced by input from a rumble strip. That is,as the vehicle tire comes into contact with the rumble strip, energyinputted into the tire causes the sensor body 241 to be displacedrelative to the mass 242. The displacement sensor 240 outputs a signalindicative of a state of displacement of the sprung mass 242 to theprocessor 190 which is adapted to receive this signal and to analyze thesignal to determine that the state of displacement of the sprung mass isindicative of tire contact with a rumble strip. A state of displacementof the sprung mass can include, for example and not by limitation,displacement speed of the sprung mass, a change in displacement speed ofthe sprung mass, and/or a rate of change of the displacement speed ofthe sprung mass. It can include location. The processor 190 can thus beconfigured to analyze a signal containing information indicative of thejust mentioned states of displacement and determine that the vehicletire is in contact with the rumble strips. The displacement sensor caninclude a distance sensor 244, a suspension stroke sensor 246 and/or anultrasonic sensor 248 to determine the state of the mass. It can alsoinclude a visual sensor and/or a laser sensor. In some embodiments ofthe present invention, any type of sensor or device that can determinethe state of displacement of a sprung mass can be used to practice thisembodiment of the invention.

Another embodiment of the present invention utilizes the relativedisplacement of a road surface having rumble strips to determine whetheror not a vehicle is coming into contact with rumble strips and/or todetermine the presence of rumble strips. An embodiment of the presentinvention utilizing the displacement of a road surface includes adisplacement sensor 250 that is adapted to determine a state ofdisplacement of a road surface relative to a location on the vehicle asthe vehicle moves along the road. The displacement sensor 250 mayinclude an ultrasonic sensor, a radar sensor, a laser and/or a visualsensor that is directed towards a road surface and detects displacementof the road surface. For example, as a vehicle drives along a road, aroad surface having rumble strips could be detected to repeatedly moveaway from the vehicle at a given frequency. Alternatively, in a roadhaving rumble strips having the bump configuration, the road surfacewould repeatedly move towards the vehicle. A processor 190 can be incommunication with the displacement sensor 250 and receive a signal fromthe displacement sensor 250 indicative of the state of displacement ofthe road with respect to this location on the vehicle. The processor 190may analyze this signal and determine whether the state of displacementof the road is indeed indicative of the presence of a rumble strip basedon the signal. For example, the processor could include logic todistinguish a state of displacement indicative of a rumble strip from,for example, displacement resulting from a pothole or a grated sewer,etc. A device utilizing such a displacement sensor can be configuredwith a displacement sensor that is adapted to output a signal that isindicative of the displacement speed, a change in displacement speedand/or a rate of change in displacement speed of the road surfacerelative to a location on the vehicle as well as the distance of thesurface or the change in distance of the surface from the vehicle and/orrelative to the road. The displacement sensor 250 would output a signalindicative of these states of displacement which could then be receivedby the processor 190, which analyzes the signal to determine that thedata regarding the state of surface displacement from the displacementsensor 250 is indicative of the presence of a rumble strip. Someembodiments of the present invention can be practiced with any type ofdisplacement sensor that can be configured to determine a state ofdisplacement of the road, providing that the sensor outputs a signalthat can be analyzed to determine the presence and/or absence of arumble strip.

Vehicle-Rumble Strip Distance

In another embodiment of the present invention, there is a device thatis configured to utilize rumble strips on a road to determine thedistance, specifically, the lateral distance that a vehicle has traveledbeyond the rumble strips. In a road departure scenario, when a vehiclebegins to deviate from a road lined with rumble strips, the vehicleencounters rumble strips, and if the driver does not take correctiveactions to steer the vehicle back into the lane, the vehicle willcontinue past the rumble strips and, eventually, if no corrective actionis taken, completely off the road. Such a road departure scenario isdepicted in FIG. 4. A device according to the present inventionestimates the lateral displacement of a vehicle based on the location ofthe rumble strips with respect to the vehicle. By lateral displacement,it is meant the direction substantially normal to the direction that therumble strips are aligned. For example, on a straight and uniform road,where the rumble strips are aligned substantially parallel to the edgeof the road, the direction of lateral displacement from the rumblestrips would be substantially normal to the edge of the road.

Estimation of the lateral displacement of the vehicle from the rumblestrip can include the use of a processor 190 that is adapted to receivesignals indicative of contact of a rumble strip with respective tires ofthe vehicle and to estimate or otherwise determine a lateral distancethat the vehicle has traveled beyond the detected rumble strip based onthese signals. One exemplary embodiment of the invention utilizes arumble strip sensor associated with each tire of a four-tire vehicle: afront right rumble strip sensor, a front left rumble strip sensor, arear right rumble strip sensor and a rear left rumble strip sensor. Theprocessor is configured to receive signals from each of these sensors,and, based on which sensor is outputting a received signal, estimate thedistance that the vehicle has traveled beyond the detected rumble strip.For example, if the front right sensor outputs a signal to the processorindicative of contact of the front right tire with a rumble strip, andthe vehicle is driving on a US road (right side driving), the processorcan estimate that the vehicle has traveled about a certain distance pastthe rumble strip (discussed in greater detail below) depending on thevehicle geometry (which may be the distance that a front bumperoverhangs the front tire, etc.). Conversely, if the rear left sensoroutputs a signal indicative of contact with a rumble strip, theprocessor could estimate the lateral distance of the vehicle based onthe vehicle geometry. FIG. 4 shows an evolving road departure scenariowhere each of the four tires come into contact with a rumble strip asthe vehicle departs from the lane. As can be seen from FIG. 4, atlocation A, only the front right tire 2010 is in contact with the rumblestrip, whereas at location D, only the rear left tire 2030 is in contactwith the rumble strip, and thus the rear left sensor is the only sensoroutputting a signal indicative of contact with the rumble strip.

As noted above, the processor can utilize information on vehiclegeometry relating to the distance between specific locations on thevehicle. For example, the front right fender of the vehicle and thelocation of one, two, three, four (or more) tires of the vehicle. Thisinformation can be stored in the processor and utilized to estimate thelateral distance that the vehicle has traveled beyond the detectedrumble strip. In another embodiment, the processor is adapted toestimate the lateral distance that the vehicle has traveled beyond thedetected rumble strips based on the order in which the signals arereceived by the processor, the order representing the order in which thetires of the vehicle contact a rumble strip. In another embodiment ofthe invention, the processor is adapted to estimate a lateral distancethat the vehicle has traveled beyond a detected rumble strip based onthe time between receiving a first signal by the processor indicative ofcontact of a rumble strip with an associated tire and the receipt of asecond signal by the processor indicative of contact of a rumble stripwith a second associated tire. For example, if 1) it is know which tireis contacting the rumble strips and which tire previously contacted therumble strips, 2) the distance between the tire currently contacting therumble strips and the tire previously contacting the rumble strips isknown, and 3) the time between the previous contact and the currentcontact is known, the direction of vehicle deviation may be estimated,and, utilizing, for example, geometry, the lateral displacement distancemay be determined. In yet another embodiment of the present invention,the processor is further adapted to estimate the lateral distance thatthe vehicle has traveled beyond the detected rumble strip based on thelongitudinal speed of the vehicle. For example if the angle of deviationfrom the rumble strip is known (deviation angle determination describedin greater detail below) and the time from first contact with the rumblestrip is also known, the lateral displacement of the vehicle can bedetermined based on the longitudinal velocity of the vehicle utilizinggeometric principles.

The present invention includes a device adapted to issue a vehiclecontrol command after a determination has been made that the vehicle isdeviating from a lane or beginning to deviate from a lane, which may bebased on the determination of contact with the rumble strips. One typeof vehicle control may include vehicle yaw control or lateral controlsystems utilizing steer by wire, a steering control actuator installedon a steering column, or a steering gear device. Vehicle yaw control orlateral control may also be obtained by issuing commands to an electricpowered and/or a hydraulic powered steering unit. Vehicle yaw control orlateral control may be accomplished by utilizing brake controls, such asa brake by wire system, a brake actuator of an antilock brake system,dynamic control systems, automatic cruise control, engine control and/oran automatic transmission control. Still further, as will be explainedin greater detail below, a passive safety system may be implemented whenit has been determined that the vehicle is coming into contact withrumble strips and is deviating into an oncoming lane. The presentinvention can be practiced with any device that alerts and/or informsthe driver that the vehicle is contacting rumble strips. This caninclude an auditory warning, such as a buzzer, audio speaker, etc., avisual warning, such as an indicator and/or a blinking light, a tactilewarning, an emitted fragrance or odor, the opening and/or closing ofwindows when a particular side of the vehicle or all of the windows ofthe vehicle, a tightening of seatbelts and/or the locking of doors. Themeans of alert may also result in the preparation of the vehicle for thepossibility of a crash since contact with rumble strips tends to occurprior to a vehicle running off the road or into an oncoming lane whenthe road that the vehicle is traveling on is furnished with rumblestrips.

In view of this, it is also noted that the present invention includescontrol of the vehicle and/or a warning issuance to a driver based onthe lateral distance that the vehicle has traveled from the rumblestrips. That is, a control unit can be used to automatically steer thevehicle back onto the road. A warning device as described above can alsobe activated. For example, referring to FIG. 4, at location A, where thefront right tire 2010 first contacts the rumble strip, a warning isissued to the driver by, for example, a speaker. As the vehicle travelspast the rumble strip as shown at positions B, C and D, control commandscan be issued in an attempt to keep the vehicle from driving off theroad. Different levels of commands/vehicle control commands/warning maybe issued based on the lateral distance that the vehicle travels pastthe rumble strip as determined by the device just discussed above. Thatis, a more radical control command would be issued at position D asopposed to position B.

In yet other embodiments of the present invention, the processor isadapted to receive signals indicative of contact of a rumble strip withrespect to associated tires and to estimate a direction in which thevehicle is traveling with respect to the direction of the detectedrumble strips. The processor can do this, for example, utilizinginformation regarding vehicle geometry relating to the distance betweena given location on the vehicle and one or more of the tires. A deviceto determine the direction in which the vehicle is traveling withrespect to the rumble strips can include a processor which is adapted toestimate the direction based on the time between reception of the firstsignal by the processor that is indicative of a contact of a rumblestrip with an associated tire and reception of a second signal by theprocessor that is indicative of contact of a rumble strip with anassociated different tire. Still further, other embodiments of thepresent invention include a processor that is adapted to estimate thedirection in which the vehicle is traveling with respect to thedirection of the plurality of the detected rumble strips based on thelongitudinal speed of the vehicle.

In another embodiment of the present invention, there is a device forestimating a lateral displacement velocity (i.e., the velocity away fromthe rumble strips) of a vehicle. For example, the present inventionincludes a device to estimate the displacement velocity based on thelocation of rumble strips with respect to the vehicle. The device cancomprise a processor which is adapted to receive a first signal and asecond signal indicative of contact of a rumble strip with associatedtwo tires of the vehicle. The processor is adapted to estimate thelateral speed at which the vehicle is traveling away from the detectedrumble strip based on the time period between receipt of the firstsignal by the processor and receipt of the second signal by theprocessor, and also a tread distance, Td, between the two tires.

FIGS. 5 and 6 show a tread distance, Td, between two tires of theautomobile. The tread distance can be the distance between a front lefttire and a front right tire, or can be the distance between a rear lefttire and a rear right tire. The tread distance may be measured betweenthe inside of the respective tires or may be the distance from theoutside of the respective tires, or may be the distance between thecenter of the front left tire and the center of the front right tire orthe center of a rear left tire and the center of a rear right tiredepending on the accuracy that is desired for the calculation of lateralvelocity away from the rumble strips. It could also be from the outsideof one tire and the inside of another tire. It may also be any otherdistance that is representative of lateral tire spacing.

The determination of the lateral displacement velocity away from therumble strips is schematically illustrated in FIG. 5 a. FIG. 5 a shows avehicle at position A and at position B. At position A, the vehicle'sfront right tire comes into contact with the rumble strip at time T1. Atposition B, the vehicle's front left tire comes into contact with therumble strip at T2. The difference between times T1 and T2 is Δt, andtherefore, the time period between when the first signal is received bythe processor and when the second signal is received is Δt. A rumblestrip sensor associated with a front right tire and a rumble stripsensor associated with the front left tire output signals indicative ofcontact with a rumble strip at times T1 and T2. By dividing the treaddistance, Td, by Δt, the lateral displacement speed, Dv may bedetermined, as shown below:Dv=Td/Δt  (1)where,

-   -   Td=tread distance, and    -   Δt=time between receiving the first signal and receiving the        second signal.

In one embodiment of the invention, the processor is configured tocalculate Dv. However, in other embodiments of the invention, a lookuptable for various tread distances, Td, and time periods, Δt, may be usedto determine the lateral speed of the vehicle, as thus determination ofDv is based on Td and Δt, as in equation (1). It is noted that the term“based on,” when used herein, is used broadly. That is, for example, anymethod or device that estimates/determines Dv utilizing informationrelating to Td and Δt, such as utilizing a lookup table, is stilldetermination of Dv based on Td and Δt, just as any device or methodthat estimates/determines Dv utilizing information relating to equation(1) above is still determination of Dv based on equation (1). Stillfurther, any means, device or method to determine Dv may be used topractice the present invention.

Vehicle Heading with Respect to Rumble Strip

In another embodiment of the invention, there is a device that isconfigured to estimate the heading of a vehicle away from a rumblestrip. As with the embodiments described above, this device can includea processor. The processor according to this embodiment is adapted toreceive a first signal and a second signal indicative of contact of arumble strip with associated two tires of the vehicle, again as with theembodiment just described. However, this processor is adapted toestimate or otherwise determine an angle at which the vehicle istraveling away from the rumble strips based on the time period Δtbetween when the first signal was received by the processor and when thesecond signal was received by the processor, along with the longitudinalvehicle speed and a tread distance between the two tires. In essence,the processor utilizes the same information as the processor describedabove, plus the longitudinal vehicle speed, to determine the vehicle'sheading away from the rumble strips. As shown in FIG. 5 b, the directionof heading away from the rumble strip θ is determined based on theopposite leg and adjacent leg of a right triangle. The opposite leg ofthe right triangle is the tread distance, Td, while the adjacent side ofthe right triangle is the distance that the vehicle travels from T1 toT2, which may then be used to determine θ. In an alternative embodimentof the invention, the processor receives input regarding thelongitudinal distance (L) that the vehicle has traveled between T1 andT2 in combination with Td, to determine the angle of deviation from therumble strips. Equations for calculating θ are seen below:tan θ=Td/(v·Δt)  (2)where,

-   -   Td=tread distance,    -   v=longitudinal speed of the vehicle, and    -   Δt=time between receiving the first signal and receiving the        second signal.

Vehicle Deviation Into Oncoming Lane

The present invention also includes a device for determining whether avehicle is deviating into an oncoming lane of an undivided highway bydetermining that a vehicle is coming into contact with rumble strips. Inthis regard, the present invention includes a processor that is adaptedto receive a first signal that is indicative of contact of a rumblestrip with the tire of a vehicle, for example, from a rumble stripsensor as described above. The processor is further adapted to receive asecond signal that is indicative of a sensor sensing an oncomingautomobile in front of the vehicle. This second signal can be from, forexample, a RADAR system, and be indicative of a RADAR return or thelike. Other embodiments could utilize a laser system to determine thatthere is an oncoming automobile ahead of the vehicle. (Indeed, anymeans, method or device that may be used to determine that there is anautomobile ahead of the vehicle may be used to practice the presentinvention.) Once the processor has received the first signal indicativeof contact of a rumble strip and also receives the second signalindicative of an oncoming automobile ahead of the vehicle, the processordetermines that the vehicle is deviating into an oncoming lane. That is,the processor includes logic to determine that the vehicle is deviatinginto an oncoming lane when the processor has received the first signalindicative of contact with a rumble strip with the tire of the vehicleand the second signal indicative of the sensation of an oncomingautomobile ahead of the vehicle. The processor logic further can be setso that a determination that the vehicle is deviating into an oncominglane is made when the first signal and the second signal are received bythe processor at the same time. Still further, processors can be adaptedto determine a time period between receipt of the first signalindicative of contact of a rumble strip with a tire and receipt of asecond signal indicative of the sensation of an oncoming vehicle, wherethe logic of the processor determines that the vehicle is deviating intoan oncoming lane based on the time period between receipt of the firstsignal and receipt of the second signal.

A processor having such a configuration can be utilized to determinethat a vehicle is deviating into an oncoming lane in a lane departurescenario where the automobile has partially crossed into the oncominglane. That is, for example, the left front and left rear tires havealready crossed the rumble strips, but the right front and right reartires have not yet contacted the rumble strips, but the vehicle is stilldeviating into the oncoming lane. By setting a time period betweenreceipt of the first signal and the second signal or by utilizing logicthat does not require the first signal and the second signal to bereceived at the same time but instead permits a predetermined timeperiod between the receipt of the first signal and the second signal toexist, vehicle deviation into an oncoming lane according to such ascenario may still be determined.

An embodiment of the present invention also includes implementation of avariable vehicle control and/or issuance of a variable warning to thedriver based on whether the vehicle is deviating from the road, orwhether the vehicle is deviating from one lane into an oncoming lane.That is, the commands and warnings can be different depending on whetherthe vehicle is deviating from the road or into an oncoming lane. Forexample, in the case where a vehicle is deviating off the road, thevehicle control may simply be to steer the vehicle back onto the road.Whereas, in the scenario where the vehicle deviation into an oncominglane has been determined, the vehicle control command may be to bothbrake the vehicle and to steer the vehicle out of the oncoming lane intoits own lane. Still further, different warning scenarios can beassociated with the different deviation scenarios. For example, if thevehicle is deviating to the right off the road a voice speaker could beactivated to warn the driver to steer to the right, and vice versa ifthe driver is deviating into an oncoming lane.

One embodiment of the present invention includes a processor which isadapted to receive a first signal indicative of contact of a rumblestrip with a tire of the vehicle from a rumble strip sensor. Thisprocessor further includes logic to determine whether or not the vehicleis deviating into an oncoming lane and also to initiate a warning basedon the processor's determination, as well as to initiate a plurality ofwarnings, based on whether or not the vehicle is deviating into anoncoming lane. For example, as noted above, if the processor determinesthat the vehicle is not deviating into an oncoming lane (that is thevehicle is simply deviating to the right off the road), a first warningmay be issued. Whereas if the processor determines that the vehicle isdeviating into an oncoming lane the processor may initiate a secondwarning to the driver, different from the first warning.

Such an embodiment can include a first warning device that is incommunication with the processor which is adapted to issue the firstwarning, as well as a second warning device also in communication withthe processor adapted to issue the second warning to the driver. Thewarnings as noted above are different. In yet other embodiments, asingle warning device is in communication with the processor, thewarning device being adapted to issue the first warning and/or thesecond warning, where the warnings are different. In some embodiments,the warning messages comprise the same audio message, the differencebetween the first warning and the second warning being that the firstwarning is louder than the second warning. In other embodiments thefirst audio warning is different than the second audio warning.

Embodiments of the present invention also include a processor adapted toreceive a first signal indicative of contact of a rumble strip with thetire of a vehicle. The processor also includes logic to determine thatthe vehicle is deviating into an oncoming lane as discussed in any ofthe above embodiments, as well as logic to initiate a vehicle controlcommand to either automatically steer the vehicle away from the oncominglane and/or to automatically brake the vehicle once the processor hasreceived the first signal indicative of contact of a rumble strip withthe tire of a vehicle. The logic can also determine that the vehicle isdeviating into an oncoming lane. Such a device may also include aprocessor having logic to initiate a warning to a driver of a vehicle ifthe processor has received the first signal indicative of contact of arumble strip with a tire and has determined that the vehicle is notdeviating into an oncoming lane.

Deviation into an oncoming lane may be determined utilizing otherdevices as well. For example, a GPS with or without a digital map of theroadway can be used to determine if a vehicle is veering onto anoncoming lane. Still further, the present invention may utilize a devicethat is adapted to determine what type of rumble strip the vehicle iscontacting. That is, on some roadways, rumble strips in the center ofthe road (e.g. in-between two oncoming lanes) are of differentconfigurations/spaced differently than rumble strips on the edges of theroad. If the vehicle is equipped with a sensor or processor that candifferentiate between different types of rumble strips, a determinationas to whether or not the vehicle is deviating into an oncoming lane canbe made. Indeed, the present invention may be utilized with any devicethat can provide an indication or otherwise determine whether or not avehicle is running off the road and/or running into an oncoming lane.For example, a processor that is configured to receive a first signalthat is indicative of both contact with a rumble strip and also the typeof rumble strip that is coming into contact with a tire may be utilizedand the processor may include logic to analyze the first signal anddetermine whether or not a vehicle is deviating into an oncoming lanebased on the type of rumble strip in contact with the tire. Such adevice can utilize a signal received from a rumble strip sensorindicative of the frequency of contact with the rumble strips and thetire. For example if the rumble strips are spaced “more closely”in-between lanes as opposed to on the edges of a road, the frequency ofcontact with such a rumble strip should be higher, and thus, based onthe velocity of the vehicle, a processor can utilize logic to analyzethe frequency and determine whether or not the vehicle is running on acenter rumble strip or on a side rumble strip, and thus determinewhether or not the vehicle is deviating into an oncoming lane.

Other embodiments of the present invention can fuse a vehicle basedsensor and rumble strip detection sensors together to determine whetheror not the vehicle is deviating into an oncoming lane. For example, avision based sensor can be combined with a rumble detection sensor toimplement the embodiments just described.

A device for implementing the above embodiment can also include avehicle control unit which is in communication with the processor and isconfigured to steer and brake the vehicle. The vehicle control unit canbe of an intelligent design which determines how the vehicle should becontrolled, or can be of a dumb design receiving input from a processoror another device as to how the vehicle should be controlled. As withthe embodiments discussed above, such a device may utilize GPS with orwithout a digital map to determine that the vehicle is deviating into anoncoming lane. Still further, the processor may be adapted to receive asignal indicative of the type of rumble strip in contact with the tireand thus determine whether or not the vehicle is deviating from theroad. In embodiments where the signal received by the processor can beindicative of the frequency of contact with the rumble strip, theprocessor can be configured to utilize this information to determinewhat type of rumble strip is coming into contact with the tire and thuswhether or not the vehicle is deviating into an oncoming lane.

Vehicle Stability Control

One embodiment of the present invention includes a device that isadapted to alter the stability characteristics, and thus the handlingcharacteristics, of a vehicle, after the vehicle has come into contactwith the road departure warning installation installed on the road, suchas a rumble strip. Such a device can be configured to receiveinformation indicative of contact of a rumble strip, and then to issue acommand to change the state of a vehicle stability component or vehiclestability system once it has been determined that the vehicle is indeedcoming into contact with rumble strips. One example of such a device isa processor that is adapted to receive a first signal from a rumblestrip sensor indicative of contact of a rumble strip with a tire of avehicle. This processor can include logic to determine that the vehicleis indeed deviating from the road, which may be based on the receivedsignal, and then to issue commands to change the state of a variablevehicle stability component or variable vehicle stability system oncethis processor has received the signal and determined that the vehicleis deviating from the road. A variable vehicle stability component orsystem can include a suspension system of the vehicle. This suspensionsystem can be automatically adjustable to increase the stability of thevehicle in response to the receipt of the command from the processor toincrease vehicle stability. The vehicle suspension system can include asuspension spring or shock absorber in communication with the processorwhere the spring constant and/or dampening factor of the suspensionspring or the shock absorber, respectively, is automatically adjustablein response to receipt of the command from the processor to altervehicle stability. For example, the suspension springs can becomestiffer and/or the dampening factor of the shock absorber may increaseso that when the driver commences corrective maneuvers to steer thevehicle back onto the lane, the vehicle's handling characteristics willbe better.

A variable vehicle stability component or vehicle stability system thatmay be used with the above-described embodiment includes a front-rearroll-rigidity proportion control unit. This control unit can beautomatically adjustable to increase the stability of the vehicle inresponse to receipt of the command from the processor to increasevehicle stability after the processor has determined that the vehicle isdeviating from the road.

Another embodiment of the present invention utilizing a variable vehiclestability control component or vehicle stability system in communicationwith the above-described processor includes a device that is adapted toautomatically lower the height of the vehicle in response to the receiptof the command from the processor to alter vehicle stability after theprocessor has determined that the vehicle is deviating from the road andto issue the command to alter vehicle stability. Another embodiment ofthe invention includes a vehicle stability component or vehiclestability system having a variable steering gear ratio control unitwhich is adapted to automatically vary the steering gear ratio inresponse to receipt of the command from the processor to increasevehicle stability. By varying the steering gear ratio, the stability ofthe vehicle may thus be altered such that when the driver takescorrective action, the vehicle handles better.

It is noted that an active hydraulic suspension system and an airsuspension system may be utilized to lower the vehicle height to reducethe moment of rotation during corrective steering. Still further, ashock absorber dampener control and/or a spring control system may beutilized in a front-rear roll-rigidity proportion control unit.

Still further, in a variable front-rear roll-rigidity proportion system,the vehicle stability may be increased by a change in the shock absorberdampener and/or the spring constants of the springs utilizing an activehydraulic suspension and/or air suspension system, an active dampenercontrol suspension system, etc. Indeed, any device or method that canincrease the stability of the vehicle after it has been determined thatthe vehicle is contacting rumble strips may be used to practice thepresent invention.

Rumble Strip Detection Correlated to Road Type

Another embodiment of the present invention relates to a method and arelated device for more accurately detecting the presence of rumblestrips contacting the tire of a vehicle. According to this embodiment ofthe invention, the type of road that the vehicle is driving on isidentified or otherwise determined so that the rumble strips may bedetected more accurately, and thus reduce “false alarm” rates of rumblestrip detection. Input from a rumble strip is different depending onwhether the rumble strip is on a concrete or asphalt road. On concreteroads, input from rumble strips is small. On the other hand, on asphaltroads, input from rumble strips is larger than that of concrete roads.However, the input from a concrete road without rumble strips tends tobe much larger than the input from an asphalt road without rumblestrips. This means that the change in input upon encountering a rumblestrip on an asphalt road is much larger than the change in input whenencountering a rumble strip on concrete. This phenomenon is illustratedin FIG. 6.

An embodiment of the present invention takes advantage of theabove-discussed phenomenon by utilizing a variable threshold input abovewhich it will be determined that the vehicle is contacting a rumblestrip. The threshold input, which must be reached before rumble stripcontact will be determined, when running on an asphalt road, will be setlarger than the threshold input set when the vehicle is running on aconcrete road, as shown in FIG. 6. When a rumble strip sensor senses anincrease in input, if the increase in input does not rise above thethreshold level set for that particular type of road, the rumble stripsensor will consider the input not to be indicative of contact with arumble strip. Conversely, if the input sensed by rumble strip sensor ishigher than the threshold level for a particular type of road, therumble strip sensor will consider the input indicative of vehiclecontact with a rumble strip.

Accordingly, an embodiment of the present invention includes a devicethat is adapted to detect a rumble strip that comes into contact with atire of the vehicle, the device comprising a road sensor that is adaptedto sense vibrational input (or other types of input) from a road surfaceinto a tire of an automobile, and output a signal indicative of thelevel of input from the road surface into the tire. The device furtherincludes a processor which is adapted to receive the signal from thesensor to determine whether the input from the road surface into thetire is indicative of input from an asphalt road or a concrete road.This processor further includes logic to determine whether input fromthe road surface is also indicative of input from a rumble strip eitherat the same time or using information from signals received at differenttimes. This logic can rely on a first level of input from the roadsurface during a first time period and a second level of input from theroad surface during the second time period after the first time period.The processor can be adapted to determine the difference between thesecond level of input and the first level of input. The processor canalso determine that the input from the road surface is indicative of theinput from the rumble strip when the difference is greater than avariable predetermined difference, the variable predetermined differencebeing greater when the vehicle is driving on an asphalt road than whenthe vehicle is driving on a concrete road. This variable difference isthe threshold levels discussed above for asphalt and for concrete.

A device according to the just described embodiment can use the samesensor to provide a signal to the processor so that the processor candetermine the type of road that the vehicle is driving on, as well as toprovide a signal so that the processor can determine whether or not thevehicle is encountering rumble strips. That is, in an exemplaryembodiment, the same vibrational sensor may be used. However, otherembodiments of the present invention may utilize a different sensor todetermine the type of road on which the vehicle is driving. For example,a sonar sensor, a RADAR sensor, a wheel speed sensor, a visual sensor,etc., may be used to determine the type of road on which the vehicle isdriving. Once a determination as to the type of road that the vehicle isdriving on is made, it is possible, in some embodiments, to simply applya “ceiling” for the received frequencies, above which if input issensed, the processor will determine that the vehicle is contacting arumble strip. That is, instead of the threshold value being added to thesensed input from the road prior to encountering rumble strips, a valueis utilized based on empirical analysis of road vibrations above whichinput will be considered as indicative of contact with a rumble strip.

Another embodiment of the present invention includes a device adapted todetect a road departure warning installation installed on a road thatcomes into contact with a tire of a vehicle comprising a road sensoradapted to sense vibrational input from a road surface into a tire of anautomobile and output a signal containing data indicative of the levelof input from the road surface into the tire. The device furtherincludes a processor adapted to receive the signal from the sensor anddetermine whether the input from the road surface into the tire isindicative of input from an asphalt road or a concrete road by comparingthe data in the signal to data stored in a look-up table indicative ofthe level of input from an asphalt road surface into the tire sensed bythe road sensor and data stored in the look-up table indicative of thelevel of input from a concrete road surface into the tire.

In view of the above, yet another embodiment of the present inventionincludes a device having a sensor adapted to sense input from a roadsurface into a tire of an automobile and output a signal containing dataindicative of the level of input from the road surface into the tire,and as well a processor that receives a second signal. The devicefurther includes a road type sensor, which can be separate and differentfrom the just described sensor, that senses the type of road that thevehicle is driving on and outputs the second signal containing dataindicative of the type of road that the vehicle is driving on. Theprocessor according to such a device receives both of the signals, and,utilizing the second signal, identifies the type of road and a thresholdlevel of input that must be found in the data of the first signal beforethe processor will determine that the vehicle tires have come intocontact with a rumble strip. This threshold value will be differentdepending on whether the road is concrete or whether the road isasphalt.

In other embodiments, a first command to the vehicle component controldevice can be to decrease a steering gear ratio of a steering gear ratiocontrol system, and a second command to the vehicle component controldevice can be to increase a dampening factor of all of a vehicle's shockabsorbers and maintain them increased for a substantial period of time.In other embodiments, the first command to the vehicle component controldevice can be to reduce the vehicle height by a predetermined amount,and the second command to the vehicle component control device can be toreduce the vehicle height so that the vehicle height is lower than thevehicle height resulting from the first command. The second command tothe vehicle component control device can be to reduce the vehicle heightso that the vehicle height is as low as possible. The processor can alsooverride the issuance of the second command if the lateral speed of thevehicle with respect to the rumble strip is greater than a predeterminedspeed, and issuance of the first command to the vehicle componentcontrol device can be to reduce the vehicle height so that the vehicleheight is as low as possible.

As discussed above, the embodiments of the present invention utilizedevices and methods where the type of road that the vehicle is drivingon is determined to set threshold levels for the detection of rumblestrips. It is desirable therefore to be able to detect the type of roadsurface that the vehicle is driving on as accurately as possible. Tothis end, the present invention includes a device that is configured toenhance road type determination. An embodiment utilizing such a deviceto better detect a road surface may utilize band-pass filters tosegregate out unneeded frequencies so that input frequencies of the roadsurfaces in the relevant frequency ranges are only outputted. Stillfurther, it is noted that in such a device, the cutoff frequency of theband-pass filters can be changed in response to the type of road surfaceas well as the vehicle velocity, the latter being available since roadsurface input vibration frequencies change with varying vehicle speed.The conceptual function of such a device can be seen at FIG. 7.

Such a device may include a road sensor which is adapted to sensevibrational input from a road surface into a tire of an automobile andoutput a signal indicative of peak vibrational input from the roadsurface into the tire. The device may also include a processor that isadapted to receive the signal from the sensor and determine whether thepeak input from the road surface into the tires is indicative of inputfrom an asphalt road or a concrete road. The processor can include logicto determine whether the input from the road surface is also indicativeof input from a rumble strip, the logic being based on a first level ofinput from the road surface during a first period of time and a secondlevel of input from the road surface during the second time period afterthe first time period. The processor can be adapted to determine thedifference between the second level of input and the first level ofinput, and to determine that the input from the road surface isindicative of input from a rumble strip if the difference is greaterthan a variable predetermined difference, the variable predetermineddifference being greater when the vehicle is driving on an asphalt roadthan when the vehicle is driving on a concrete road. Such a device mayinstead or in addition to this, utilize a processor that is adapted toreceive the signal from the sensor and determine whether the input fromthe road surface into the tire is indicative of input from an asphaltroad or concrete road by comparing the data in the signal to data storedthat is indicative of a level of input from an asphalt road surface intothe tire sensed by the road sensor and data stored that is indicative ofthe level of input from a concrete road surface into the tire. Theprocessor, is further adapted to determine whether the signal containingdata indicative of the level of the input from a road surface into atire contains data indicative of input from a rumble strip into the tirebased on the difference between the levels of input into the tire sensedby the road sensor and at least one of a level of input sensed by theroad sensor for an asphalt road stored in the lookup table and the levelof input sensed by the road sensor for a concrete road that is alsostored, in the lookup table. The processor is further adapted todetermine that the signal contains data indicative of input from arumble strip into the tire if the difference is greater than apredetermined difference, the predetermined difference being greater forasphalt roads than for concrete roads.

It is noted that other embodiments of the present invention can utilizedevices of different configurations. Indeed, any device that can makeuse of the principles of band-pass filtering vibrational frequencies, asdepicted in FIG. 7, may be used to improve road type sensing and/orrumble strip sensing, and thus can be utilized to practice the presentinvention.

Intermittent Rumble Strips and Road Deviation

Some of the devices and methods disclosed herein can be used in a systemwhere the input from a rumble strip must be continuous for apredetermined period of time so that the chances of a false alarm arereduced. Still further, some embodiments of the present inventioninclude systems that determine whether or not a driver is returning backonto the road by his or her own accord. That is, a drowsy driver may bewaken by the devices disclosed herein, and thus take the appropriatecorrective actions and drive off of the rumble strips back into thelane. Still further, some of the embodiments disclosed in the presentinvention utilize a control device to steer the vehicle away from therumble strips. Thus, in these systems, once input from the rumble stripceases, some systems are adapted to make the determination that thevehicle is no longer driving on the rumble strip. Devices having thesefeatures work well for continuous rumble strips. However, intermittentrumble strips (see FIG. 8) pose the possibility that such a device willbe tricked into thinking that the vehicle is returning to the road wheninput from the intermittent rumble strip stops due to the rumble stripsintermittency. This is seen more clearly by comparing contact with acontinuous rumble strip (FIG. 9) and contact with an intermittent rumblestrip (FIG. 10), as is done below.

FIG. 9 shows two rumble strip encounter scenarios on a continuous rumblestrip. In the first scenario, the vehicle represented by the dashedcurve contacts the rumble strip and then veers away from the rumblestrip. In the second scenario represented by the solid curve, thevehicle encounters the rumble strip and continues to drive on the rumblestrip. In embodiments of the present invention utilizing a processor todetermine whether or not the vehicle is continuing to run on a rumblestrip or whether or not the vehicle is taking corrective action based onthe length of time that the vehicle is driving on the rumble strip basedon a threshold time period (or threshold distance), the processor willdetermine that the vehicle continues to deviate from the lane in thesecond scenario, and determine that the vehicle has taken appropriatecorrective action in the first scenario. This works well in the case ofa continuous rumble strip. However, in the case of an intermittentrumble strip, where the input from the rumble strip occurs for a shortperiod of time, as seen in FIG. 10, the processor may think that thevehicle is returning to the road, when in fact the vehicle is continuingto depart from the road, and/or continuing to drive on a rumble stripbecause the period of time of rumble strip input is less than thethreshold time (or threshold distance).

To address this problem, an embodiment of the present invention canutilize an algorithm that determines the time period between receivinginput from intermittent rumble strips and determine whether or not thevehicle is departing from the road and/or continuing to contact rumblestrips based on the time period between sensing input from rumblestrips, as shown in FIG. 11. An embodiment of the present invention,therefore, includes a device comprising a processor that is adapted toreceive a series of signals indicative of repetitive contact of a rumblestrip with a tire of the vehicle as shown in FIGS. 10 and 11. Theprocessor is adapted to determine the length of time between receipt ofthe signals and includes logic to determine that the vehicle isdeviating from the road if the length of time between receipt of signalsTbetween is less than a first predetermined time period and/or Tbetweenfalls within a predetermined range of times. In the event that theprocessor does not receive a signal after the first signal within acertain period of time, or a range of time, the processor determinesthat the vehicle is returning to the lane. Thus, the device candetermine whether or not the vehicle is deviating from the road if theseries of signals arrive at the processor in a time period that isshorter than a predetermined time period, Tpredetermined (see FIG. 11).In yet another embodiment of the present invention, the processor isfurther adapted to determine the length of time that the signals arereceived and the processor includes logic to determine that the vehicleis contacting a rumble strip if the length of time that a first signalof the series of signals is received is longer than a secondpredetermined time period and to determine that the vehicle is deviatingfrom the road if the length of time between the end of receipt of thefirst signal and a beginning of receipt of a second signal, Tbetween, ofthe series of signals is less than the first predetermined time period.That is, this device has a false alarm feature that lowers the number offalse alarms by ensuring that a signal was received for at least acertain amount of time. It is noted that the first predetermined timeand the second predetermined time can be the same or may be different.

Another embodiment of the present invention comprises a processor asjust described that further includes logic to determine that the vehicleis deviating from the road if the length of time between the end ofreceipt of the first signal and the beginning of receipt of the secondsignal of the series of signals following the first signal is less thanthe first time period and the length of time that the second signal wasreceived is longer than the second predetermined time period. That is, adevice according to this embodiment also analyzes the length of timethat a second signal following the first signal is received, thusfurther reducing the chance of a false alarm Still further, anotherembodiment of the invention includes a processor that is adapted toreceive an intervening signal between the just mentioned first signaland second signal in the series of signals, where the length of timethat the intervening signal is received is shorter than the secondpredetermined time period. This embodiment addresses the possibilitythat a false signal might be received in between two valid signalsindicative of contact with rumble strips. Thus, the device includeslogic to ignore this false signal but still “look” for receipt of thesecond signal, and if the second signal begins within the predeterminedtime period following the end of receipt of the first signal, and alsopersists for a sufficient period of time to be indicative of a rumblestrip, the device then determines that the vehicle is continuing tocontact rumble strips.

Another embodiment of the present invention includes any of theprocessors just described wherein the processor further includes logicto determine whether the vehicle is continuing to depart from the roador whether the vehicle is returning to the road.

Devices as just described also may include a processor having logic toinitiate a warning to a driver of the vehicle once the processor hasdetermined that the vehicle is continuing to depart from the road and/orcontinuing to contact rumble strips. Still further, a processor utilizedin the embodiments just described may also be adapted to issue a vehiclecontrol command once the processor has determined the vehicle wascontinuing to depart from the road or continuing to contact rumblestrips. Such a device may also include a vehicle control unit incommunication with a processor which is adapted to receive the vehiclecontrol command from the processor and automatically steer the vehicleback onto the road and/or automatically brake the vehicle once theprocessor has determined that the vehicle is continuing to depart fromthe road and/or contact rumble strips. Still further, another embodimentof the present invention includes the processor described above, furtherincluding logic to determine that the vehicle is contacting a rumblestrip if the length of time that a signal, for example, the firstsignal, is received is longer than a second predetermined time period.That is, the above described device to determine whether the vehicle hasreturned to a road or is continuing to depart from the road accountingfor intermittent rumble strips can also be configured to be utilized forcontinuous rumble strips. That is, the determination that the vehicle iscontinuing to depart from the road is not dependent on the receipt of asecond signal; it can be determined based only on the first signal ifthat signal persists for long enough.

Disregarding Rumble Strip Detection

Another aspect of the present invention is directed towards determiningwhether a rumble strip detection system should ignore input from arumble strip. Such a device can be used when driving on roads that areunder construction. In some instances, roads that are under constructionhave their lanes shifted, for example, to a shoulder of a road such thatthe shoulder may become a temporary lane while another portion of theroad is under construction, thus permitting vehicles to continue using aroad. When properly driving on such a road, a vehicle may come intocontact with these rumble strips. FIG. 12 shows a road underconstruction, where the rumble strips lie substantially in the middle ofa lane. When driving on such a road, the vehicle may come into contactwith the rumble strips even though the vehicle is being driven properly.

To accomplish such a goal, an embodiment of the present inventionincludes a device that is adapted to determine whether vehicle contactwith a road departure warning installation, such as a rumble strip,installed on a road should be ignored. The device relies on informationrelating to whether or not a road is a divided road and the location ofthe rumble strip on the road to make this determination, as will now beexplained.

The device comprises a processor which is adapted to receive a signalindicative of contact of a rumble strip with the tire of the vehicle andto analyze the received signal and determine that the rumble strip hascontacted the tire. The processor is also configured to receive inputrelating to the location of the rumble strip with respect to plurality aof driving lanes. That is, the processor can receive input from forexample a RADAR system, a visual detector, or another type of sensor,that can determine whether or not the rumble strips are located withindriving lanes, such as the rumble strips shown in FIG. 12. The processoris further adapted to receive input that the vehicle is driving one ofan undivided road such as the road shown in FIG. 13. Such input couldcome from, for example a GPS system in combination with a map data baseof local roads and/or from information from roadside by Detailed ShortRange Communication, or by RADAR sensors or vision sensors that maydetect a median wall or road divider, such as that shown in FIG. 12, theabsence of such a median wall or road divider being indicative of anundivided road.

The processor according to this device further includes logic to issueat least one of a warning command and/or a vehicle control command whenit is determined that the rumble strip is located within driving lanesand that the vehicle is driving on an undivided road. That is, when thedevice senses that rumble strips are located within driving lanes and ona road that is an undivided road, the device assumes that the vehicle isdeviating into a center rumble strip on an undivided road separating thedriving lane from the oncoming lane, and thus issues a warning and/or avehicle control command so that the vehicle may take corrective action.

Road Separator Rumble Strips and Shoulder Rumble Strips

Another embodiment of the present invention is directed towardsdiscrimination between center rumble strips and shoulder rumble strips.FIG. 13 shows center rumble strips separating oncoming lanes. This iscontrasted to shoulder rumble strips which lie along the edges of lanes.In many instances, vehicle deviation into an oncoming lane will havemore serious consequences than deviation from a lane onto a shoulder ofa road. Thus, an embodiment of the present invention includes a devicethat is adapted to detect whether or not a vehicle is contacting centerrumble strips or shoulder rumble strips, and thus to determine whetheror not the vehicle is deviating into an oncoming lane or onto ashoulder. Such a device may issue a warning that alerts the driver moreaggressively when the driver is deviating into an opposite lane and/ortakes control of the vehicle and issues a control command to control thevehicle in a more aggressive manner. In some embodiments of theinvention, such a device includes a processor that is configured todistinguish center rumble strips from shoulder rumble strips based onthe pattern or the type of rumble strips. That is, because roadssometimes utilize different types of rumble strips or different rumblestrip patterns for center rumble strips, a device can be implementedinto a vehicle that can distinguish a center rumble strip pattern from ashoulder rumble strip pattern based on, for example, input frequencyfrom the rumble strips, and thus recognize if the vehicle is about todeviate from a road onto a shoulder or into an opposite traffic lane,the latter typically resulting in more severe consequences. Based onthis determination, the device can issue an appropriate warning and/ortake control of the vehicle as necessary.

Lane Marker Distance from Rumble Strips

Another embodiment of the invention takes advantage of the fact thatrumble strips on the sides of roads sometimes have varying distancesfrom a lane marker, such as can be seen in FIG. 14. By determining thedistance Wln-rs between a lane marker and a rumble strip, an embodimentof the present invention can determine the severity of a vehicledeviation, from a lane or road. Still further, by utilizing thisdistance information to judge the severity of the vehicle deviation, thepresent invention can include determination of the type of control thatshould be provided to a vehicle and/or the type of warning provided. Forexample, if the distance between the lane marker and the rumble stripsis small, for example less than the tread width, the device may simplyoutput a minor advisory to the driver to be more attentive, whereas, ifthe distance between the lane marker and the rumble strips is large, forexample, greater than the tread width, the device may output a warningforcefully commanding the driver to steer to the left. Still further, ifthe distance between the lane marker and the rumble strips is small, acontrol command outputted by the processor may be minor, as opposed towhen the distance is very large, the amount of control exerted on thevehicle being greater. An example of this variable control can be seenin the graph on FIG. 14, which shows that brake control gain increasesas the detected distance between the lane marker and the rumble stripincreases. Still further by way of example, as can again be seen in thegraph in FIG. 14, after a certain distance of lane-rumble stripseparation, the brake control grain stays the same; this distance couldbe a distance equal to and/or greater than the tread width of thevehicle. Such a control regime is also applicable to vehicle steeringcommands and/or any other command that can be used with the presentinvention.

An example of this embodiment of the invention includes a device that isadapted to determine the distance between a lane marker and a rumblestrip. The device comprises a processor which is adapted to receive afirst signal that is indicative of the crossing of a lane marker such asa painted line, by the vehicle and to receive a second signal indicativeof a lateral speed of the vehicle, and further to receive a third signalindicative of contact of a rumble strip with the tire of the vehicle.The processor is further adapted to analyze this third signal anddetermine that the rumble strip has indeed contacted the tire and alsoto determine the time period between receiving the first signal andreceiving the third signal. Further, the processor is adapted todetermine the distance between the lane marker and the rumble stripbased on the time period between receiving the first signal andreceiving the third signal as well as on the lateral speed of thevehicle. The distance between the lane marker on the rumble strip may bedetermined based on the equation:Wln-rs=Vltrl·Δtln-rswhere,

-   -   Vltrl=lateral speed of the vehicle, and    -   Δtln-rs=time between crossing the lane marker and detecting the        rumble strip.

Such a device can also include a sensor that is adapted to detect thelane marker as well as to determine that the vehicle has crossed thelane marker. Such a device can further include a visual sensor, amagnetic sensor or any sensor that will permit identification of thepresence of a lane marker and/or that the vehicle has crossed the lanemarker.

While in the just described embodiment, the vehicle's lateral speed isused to determine the distance from the lane marker and/or the distancebetween the lane marker and the rumble strip, other embodiments canutilize actual measurements of the distance between the lane marker andthe rumble strip. Such a device may include a visual sensor and/or alaser sensor that utilizes, for example, triangulation to determine thedistance from a location on the vehicle and the lane marker. Oncecontact with the rumble strip is made with the vehicle's tires, if thedistance between the location on the vehicle and the tire is known, thedistance between the rumble strip and the lane marker can also bedetermined.

As noted above, it is anticipated that once contact with a rumble stripsensor is detected, a corrective action will be made which may includesteering and/or braking. Alternatively, if corrective action is nottaken, the vehicle may likely to leave the road and/or get into someform of accident after contact with rumble strips is detected.

Specific Implementation of the Invention

FIGS. 15-25 illustrate specific implementations of the invention. One ofskill in the art will understand that these figures provided someexamples of the techniques described in detail above. Because suchtechniques have been described in detail above and/or may readily beimplemented by one of ordinary skill in the art based on the figures incombination with the teachings and knowledge in the art, a detaileddescription of these figures is not provided. FIG. 15 presents a blockdiagram of a device adapted to implement an embodiment of the presentinvention. It is noted that some embodiments can include additionalfeatures, while other embodiments need not utilize each featurepresented. For example, some embodiments can be practiced without GPS.

It is further noted that when referring to “logic” herein, “logic” isused broadly. For example, logic includes hardware, software, firmware,etc. Simple and/or complex circuits can be utilized to implement logicaccording to the present invention.

Many of the above devices and/or methods may utilize piezoelectricdevices to determine the state of various components described herein.For example, a piezoelectric device may be utilized to determine thestate of pressure in a shock absorber.

It is further noted that when referring to devices such as processorsand sensors, such devices are referred to both as a single unit and asseparate units. That is, a processor that receives a signal from asensor could include a sensor, and visa versa.

The present invention also includes software and firmware forimplementing the above and below described embodiments of the invention.In this regard, algorithms according to the present invention will nowbe described; algorithms which can form the basis for control programsand routines for implementing aspects of the invention. FIG. 16 shows aflow chart for an algorithm that utilizes the steering wheel angle andthe rate of change of the steering wheel angle to determine whether ornot the driver is taking corrective action (corrective steering) basedon whether the angle that the steering wheel is turned is greater thanor equal to a threshold angle, θth, and whether the rate of change ofthe steering wheel angle is greater or equal to a threshold rate ofchange.

In the embodiments described in the flow chart in FIG. 16 as well as thefollowing flow charts, a gravity sensor, (G sensor) is utilized as therumble strip sensor. However other sensors can be used in place of a Gsenor or in addition to a G sensor to practice the invention.

FIG. 17 provides a flow chart for an algorithm to detect rumble stripscontacting a tire of the vehicle. In the flow chart of FIG. 17, variousexemplary band-pass filters are utilized to filter out variousfrequencies in accordance with the embodiments of the inventionutilizing frequency filtering as described above.

FIG. 18 provides a flow chart for an algorithm to determine whether ornot a driver is taking corrective action according to the presentinvention.

FIG. 19 provides a flow chart for an algorithm to implement roaddeviation/departure avoidance with steering and/or brake controlaccording to the present invention. As can be seen, the flow chart ofFIG. 19 refers to the flow charts of FIGS. 17 and 18 for the detectionof rumble strips and the determination that the driver is steeringcorrectively. Still further, the flow chart of FIG. 19 refers to theflow charts of FIGS. 20 and 21 showing flow charts for algorithms forbrake and control algorithms for the control of the pre-tensioning ofseat belts according to the present invention, respectively.

The flow chart shown in FIG. 22 provides a flow chart for an algorithmfor vehicle control based on the lateral displacement of the vehiclewith respect to rumble strips. It can be seen that the flow chart ofFIG. 22 refers to the flow charts of FIGS. 17, 18, 19 and 20 for thedetection of the drivers' corrective action and the pre-tensioning ofdrivers seat belts.

FIG. 23 presents a flow chart for an algorithm to estimate or otherwisedetermine the lateral speed and the angle of deviation with respect tothe rumble strips of a vehicle after crossing rumble strips. The flowchart of FIG. 23 refers to the flow charts of FIGS. 18 and 20.

FIG. 24 provides a flow chart for an algorithm to determine whether ornot a vehicle is deviating into an opposite or oncoming lane. As withthe flow chart of FIG. 23, the flow chart of FIG. 24 refers to flowcharts of FIGS. 18, 19 and FIG. 20.

FIG. 25 presents a flow chart for an algorithm that can be utilized toimplement vehicle stability control upon the determination that thevehicle has crossed rumble strips and/or is deviating from a lane or offthe road. The flow chart of FIG. 25 refers to the flow chart of FIG. 19.

Accordingly, the present invention includes a program product andhardware for implementing the above algorithms, as well as the systemsand methods described herein, and also for the control of the devicesdescribed herein.

Given the disclosure of the present invention, one versed in the artwould appreciate that there may be other embodiments and modificationswithin the scope and spirit of the present invention. Accordingly, allmodifications within the scope and spirit of the present invention areto be included as further embodiments of the present invention. Thescope of the present invention accordingly is to be defined withreference to the appended claims.

1. A device adapted to detect a road departure warning installationinstalled on a road that comes into contact with a tire of a vehiclecomprising a rumble strip sensor adapted to sense input from a rumblestrip, wherein the sensor includes: a vibration sensor in communicationwith at least one of a sprung mass and an unsprung mass, the vibrationsensor being adapted to determine a frequency of vibration of the sprungmass or the unsprung mass and to output a signal indicative of thefrequency of vibration of the sprung mass or the unsprung mass; and aprocessor in communication with the vibration sensor and adapted toreceive the signal, wherein the processor is also adapted to analyze thesignal and determine whether the frequency of vibration is indicative oftire contact with a rumble strip based on the signal.
 2. The device ofclaim 1, wherein the vibration sensor is a gravity sensor.
 3. A deviceadapted to detect a road departure warning installation installed on aroad that comes into contact with a tire of a vehicle comprising arumble strip sensor adapted to sense input from a rumble strip, whereinthe sensor includes: a shock absorber assembly adapted to output asignal indicative of the state of a dampening portion of the shockabsorber; and a processor in communication with the shock absorberassembly and adapted to receive the signal, wherein the processor isalso adapted to analyze the signal and determine whether the shockabsorber is absorbing shock indicative of tire contact with a rumblestrip based on the signal.
 4. The device of claim 3, wherein the shockabsorber assembly is adapted to output a signal indicative of at leastone of a pressure, a change in pressure, and a rate of change inpressure in a dampening portion of the shock absorber, and wherein theprocessor is also adapted to analyze the signal and determine whetherthe pressure, change in pressure, and the rate of change in pressure inthe dampening portion of the shock absorber is indicative of tirecontact with a rumble strip based on the signal.
 5. A device adapted todetect a road departure warning installation installed on a road thatcomes into contact with a tire of a vehicle comprising a rumble stripsensor adapted to sense input from a rumble strip, wherein the sensorincludes: a wheel assembly adapted to output a signal indicative of thestate of compression in a tire portion of the wheel assembly; and aprocessor in communication with the wheel assembly and adapted toreceive the signal, wherein the processor is also adapted to analyze thesignal and determine whether the state of compression is indicative oftire contact with a rumble strip based on the signal.
 6. The device ofclaim 5, wherein the wheel assembly is adapted to output a signalindicative of at least one of a pressure, a change in pressure, and arate of change in pressure in the tire, and wherein the processor isalso adapted to analyze the signal and determine whether the pressure,change in pressure, and the rate of change in pressure is indicative oftire contact with a rumble strip.
 7. A device adapted to detect a roaddeparture warning installation installed on a road that comes intocontact with a tire of a vehicle comprising a rumble strip sensoradapted to sense input from a rumble strip, wherein the sensor includes:a wheel assembly adapted to output a signal indicative of a state ofrotation of at least a portion of the wheel assembly; and a processor incommunication with the wheel assembly and adapted to receive the signal,wherein the processor is also adapted to analyze the signal anddetermine whether the state of rotation of the portion of the wheelassembly is indicative of tire contact with a rumble strip based on thesignal.
 8. The device of claim 7, wherein the wheel assembly is adaptedto output a signal indicative of at least one of a rotation speed, achange in rotation speed, and a rate of change in rotation speed of theportion of the wheel assembly, and wherein the processor is also adaptedto analyze the signal and determine whether the rotation speed, thechange in rotation speed, and the rate of change in rotation speed ofthe portion of the wheel assembly is indicative of tire contact with therumble strip based on the signal.
 9. A device adapted to detect a roaddeparture warning installation installed on a road that comes intocontact with a tire of a vehicle comprising a rumble strip sensoradapted to sense input from a rumble strip, wherein the sensor includes:a microphone adapted to output a signal indicative of sound sensed bythe microphone; and a processor in communication with the microphone andadapted to receive the signal, wherein the processor is also adapted toanalyze the signal and determine whether sound sensed by the microphoneis indicative of tire contact with a rumble strip based on the signal.10. A device adapted to detect a road departure warning installationinstalled on a road that comes into contact with a tire of a vehiclecomprising a rumble strip sensor adapted to sense input from a rumblestrip, wherein the sensor includes: a displacement sensor including asprung mass, the displacement sensor being adapted to determine a stateof displacement of the sprung mass which is displaced by input from arumble strip and output a signal indicative of the state ofdisplacement; and a processor in communication with the displacementsensor and adapted to receive the signal, wherein the processor is alsoadapted to analyze the signal and determine whether the state ofdisplacement of the sprung mass is indicative of tire contact with arumble strip based on the signal.
 11. The device of claim 10, whereinthe displacement sensor comprises at least one of a distance sensor, asuspension stroke sensor, and an ultra-sonic sensor.
 12. The device ofclaim 10, wherein the displacement sensor is adapted to output a signalindicative of at least one of a displacement speed, a change indisplacement speed, and a rate of change in displacement speed of thesprung mass, and wherein the processor is also adapted to analyze thesignal and determine whether the displacement speed, the change indisplacement speed, and the rate of change in displacement speed of thesprung mass is indicative of tire contact with a rumble strip based onthe signal.
 13. A device adapted to detect a road departure warninginstallation installed on a road that comes into contact with a tire ofa vehicle comprising a rumble strip sensor adapted to detect thepresence of a rumble strip, wherein the sensor includes: a displacementsensor adapted to determine a state of displacement of a road surfacerelative to a location on the vehicle as the vehicle moves along theroad and to output a signal indicative of the state of displacement; anda processor in communication with the displacement sensor and adapted toreceive the signal, wherein the processor is also adapted to analyze thesignal and determine whether the state of displacement of the roadsurface is indicative of the presence of a rumble strip based on thesignal.
 14. The device of claim 13, wherein the displacement sensor isadapted to output a signal indicative of at least one of a displacementspeed, a change in displacement speed, and a rate of change indisplacement speed of the road surface relative to the location on thevehicle, and wherein the processor is also adapted to analyze the signaland determine whether the displacement speed, the change in displacementspeed, and the rate of change in displacement speed of the road surfacerelative to the location on the vehicle is indicative of the presence ofa rumble strip based on the signal.
 15. A device adapted to estimatelateral displacement of a vehicle based on the location of a roaddeparture warning installation installed on a road with respect to thevehicle, comprising: a processor adapted to receive four signalsindicative of contact of a rumble strip with respective associated fourtires of the vehicle, wherein the processor is further adapted toestimate a lateral distance that the vehicle has traveled beyond thedetected rumble strip based on which of the four tires is associatedwith a respective signal.
 16. The device according to claim 15, whereinthe processor contains information on a vehicle geometry relating to thedistance between at least one location on the vehicle and at least oneof the four tires, and wherein the processor is adapted to utilize theinformation to estimate the lateral distance that the vehicle hastraveled beyond the detected rumble strip.
 17. The device according toclaim 15, wherein the processor is further adapted to estimate thelateral distance that the vehicle has traveled beyond the detectedrumble strip based on the order in which the signals are received by theprocessor.
 18. The device according to claim 15, wherein the processoris further adapted to estimate the lateral distance that the vehicle hastraveled beyond the detected rumble strip based on the time between afirst signal reception by the processor indicative of contact of arumble strip with an associated first tire and a second signal receptionby the processor indicative of contact of a rumble strip with anassociated second tire.
 19. The device according to claim 18, whereinthe processor is further adapted to estimate the lateral distance thatthe vehicle has traveled beyond the detected rumble strip based on thelongitudinal speed of the vehicle.
 20. A device adapted to estimatelateral displacement of a vehicle based on the location of a roaddeparture warning installation installed on a road with respect to thevehicle, comprising: a processor adapted to receive four signalsindicative of contact of a rumble strip with respective associated fourtires of the vehicle, wherein the processor is further adapted toestimate a direction in which the vehicle is traveling with respect tothe direction of a plurality of detected rumble strips based oninformation contained in the processor regarding a vehicle geometryrelating to the distance between at least one location on the vehicleand at least one of the four tires.
 21. The device according to claim20, wherein the processor is further adapted to estimate the directionin which the vehicle is traveling with respect to the direction of theplurality of detected rumble strips based on the time between a firstsignal reception by the processor indicative of contact of a rumblestrip with an associated first tire and a second signal reception by theprocessor indicative of contact of a rumble strip with an associatedsecond tire.
 22. The device according to claim 20, wherein the processoris further adapted to estimate the direction in which the vehicle istraveling with respect to the direction of the plurality of detectedrumble strips based on the longitudinal speed of the vehicle.
 23. Adevice adapted to estimate lateral displacement velocity of a vehiclebased on the location of a road departure warning installation installedon a road with respect to the vehicle, comprising: a processor adaptedto receive at least a first signal and a second signal indicative ofcontact of a rumble strip with respective associated two tires of thevehicle, wherein the processor is further adapted to estimate a lateralspeed at which the vehicle is traveling away from a detected rumblestrip based on: a time period between when the first signal is receivedby the processor and when the second signal is received by theprocessor; and a tread distance between the two tires.
 24. The deviceaccording to claim 23, wherein the estimation of lateral speed (Dv) isdetermined based on the equation:Dv=Td/Δt where, Td=tread distance, and Δt=time between receiving thefirst signal and receiving the second signal.
 25. A device adapted toestimate the heading of a vehicle based on the location of a roaddeparture warning installation installed on a road with respect to thevehicle, comprising: a processor adapted to receive at least a firstsignal and a second signal indicative of contact of a rumble strip withrespective associated two tires of the vehicle, wherein the processor isfurther adapted to estimate an angle at which the vehicle is travelingaway from a plurality of detected rumble strips based on: a time periodbetween when the first signal is received by the processor and when thesecond signal is received by the processor; a longitudinal vehiclespeed; and a tread distance between the two tires.
 26. The deviceaccording to claim 25, wherein the estimation of the angle (θ) at whichthe vehicle is traveling away from the plurality of detected rumblestrips (Dv) is determined based on the equation:tan θ=Td/(v·Δt) where, Td=tread distance, v=longitudinal speed of thevehicle, and Δt=time between receiving the first signal and receivingthe second signal.
 27. A device adapted to determine whether a vehicleis deviating into an oncoming lane of an un-divided highway, comprising:a processor adapted to receive at least a first signal indicative ofcontact of a rumble strip with a tire of the vehicle, wherein theprocessor is further adapted to receive a second signal indicative of aRADAR return of an oncoming vehicle, the processor including logic to:determine that the vehicle is deviating into an oncoming lane when theprocessor has received the first signal and the second signal.
 28. Thedevice according to claim 27, wherein the logic determines that thevehicle is deviating into an oncoming lane when the first signal and thesecond signal are received by the processor at the same time.
 29. Thedevice according to claim 27, wherein the processor is adapted todetermine the time period between receipt of the first signal and thesecond signal, and wherein the logic determines that the vehicle isdeviating into an oncoming lane based on the time period between receiptof the first signal and receipt of the second signal.
 30. A deviceadapted to detect a road departure warning installation installed on aroad that comes into contact with a tire of a vehicle, comprising: aroad sensor adapted to sense vibrational input from a road surface intoa tire of a vehicle and output a signal indicative of the level of inputfrom the road surface into the tire; and a processor adapted to receivethe signal from the sensor and determine whether the input from the roadsurface into the tire is indicative of input from an asphalt road or aconcrete road, wherein the processor includes logic to determine whetherthe input from the road surface is also indicative of input from arumble strip, the logic being based on: a first level of input from theroad surface during a first time period; and a second level of inputfrom the road surface during a second time period after the first timeperiod; wherein the processor determines the difference between thesecond level of input and the first level of input; and the processordetermines that the input from the road surface is indicative of inputfrom a rumble strip if the difference is greater than a variablepredetermined difference, the variable predetermined difference beinggreater when the vehicle is driving on an asphalt road than when thevehicle is driving on a concrete road.
 31. A device adapted to detect aroad departure warning installation installed on a road that comes intocontact with a tire of a vehicle comprising: a road sensor adapted tosense vibrational input from a road surface into a tire of a vehicle andoutput a signal containing data indicative of the level of input fromthe road surface into the tire; and a processor adapted to receive thesignal from the sensor and determine whether the input from the roadsurface into the tire is indicative of input from an asphalt road or aconcrete road by comparing the data in the signal to data storedindicative of the level of input from an asphalt road surface into thetire sensed by the road sensor and data stored indicative of the levelof input from a concrete road surface into the tire; wherein theprocessor is further adapted to determine whether the signal containingdata indicative of the level of input from a road surface into the tirecontains data indicative of input from a rumble strip into the tirebased on: the difference between the stored level of input into the tiresensed by the road sensor and at least one of the stored level of inputfor an asphalt road and the stored level of input for a concrete road;wherein the processor determines that the signal contains dataindicative of input from a rumble strip into the tire if the differenceis greater than a predetermined difference, the predetermined differencebeing greater for asphalt roads than for concrete roads.
 32. A deviceadapted to detect a road departure warning installation installed on aroad that comes into contact with a tire of a vehicle comprising: a roadsensor adapted to sense vibrational input from a road surface into atire of a vehicle and output a signal indicative of peak vibrationalinput from the road surface into the tire; and a processor adapted toreceive the signal from the sensor and determine whether the peak inputfrom the road surface into the tire is indicative of input from anasphalt road or a concrete road, wherein the processor includes logic todetermine whether the input from the road surface is also indicative ofinput from a rumble strip, the logic being based on: a first level ofinput from the road surface during a first time period; and a secondlevel of input from the road surface during a second time period afterthe first time period; wherein the processor determines the differencebetween the second level of input and the first level of input; and theprocessor determines that the input from the road surface is indicativeof input from a rumble strip if the difference is greater than avariable predetermined difference, the variable predetermined differencebeing greater when the vehicle is driving on an asphalt road than whenthe vehicle is driving on a concrete road.
 33. The device according toclaim 32, wherein the device includes a band-pass filter adapted tofilter out vibrational frequencies.
 34. The device according to claim32, wherein the band-pass filter is a variable band-pass filter adaptedto filter out different frequencies based on vehicle velocity.
 35. Thedevice according to claim 32, wherein the processor is adapted toreceive information relating to longitudinal velocity of the vehicle andoutput a signal indicative of peak vibrational output from the roadsurface into the tire based on the longitudinal velocity.
 36. A deviceadapted to detect a road departure warning installation installed on aroad that comes into contact with a tire of a vehicle comprising: a roadsensor adapted to sense vibrational input from a road surface into atire of a vehicle and output a signal containing data indicative of thepeak vibrational input from the road surface into the tire; and aprocessor adapted to receive the signal from the sensor and determinewhether the input from the road surface into the tire is indicative ofinput from an asphalt road or a concrete road by comparing the data inthe signal to data stored indicative of the level of input from anasphalt road surface into the tire sensed by the road sensor and datastored indicative of the level of input from a concrete road surfaceinto the tire; wherein the processor is further adapted to determinewhether the signal containing data indicative of the level of input froma road surface into the tire contains data indicative of input from arumble strip into the tire based on: the difference between the level ofinput into the tire sensed by the road sensor and at least one of thestored level of input for an asphalt road and the stored level of inputfor a concrete road; wherein the processor determines that the signalcontains data indicative of input from a rumble strip into the tire ifthe difference is greater than a predetermined difference, thepredetermined difference being greater for asphalt roads than forconcrete roads.
 37. The device according to claim 36, wherein the deviceincludes a band-pass filter adapted to filter out vibrationalfrequencies.
 38. The device according to claim 37, wherein the band-passfilter is a variable band-pass filter adapted to filter out differentfrequencies based on vehicle velocity.
 39. The device according to claim36, wherein the processor is adapted to receive information relating tolongitudinal velocity of the vehicle and output a signal indicative ofpeak vibrational output from the road surface into the tire based on thelongitudinal vehicle velocity.
 40. A device adapted to determine whethera vehicle is deviating from a road, comprising: a processor adapted toreceive a series of signals indicative of contact of a rumble strip witha tire of the vehicle, wherein the processor is further adapted todetermine the length of time between receipt of the signals, and whereinthe processor includes logic to: determine that the vehicle is deviatingfrom the road if the length of time between receipt of the signals isless than a first predetermined time period.
 41. The device according toclaim 40, wherein the processor is further adapted to determine thelength of time that the signals are received, and wherein the processorfurther includes logic to: determine that the vehicle is contacting arumble strip if the length of time that a first signal of the series ofsignals is received is longer than a second predetermined time period;and determine that the vehicle is deviating from the road if the lengthof time between the end of receipt of the first signal and a beginningof receipt of a second signal of the series of signals is less than thefirst predetermined time period.
 42. The device according to claim 41,wherein the processor further includes logic to: determine that thevehicle is deviating from the road if the length of time between the endof receipt of the first signal and a beginning of receipt of the secondsignal of the series of signals following the first signal is less thanthe first predetermined time period and the length of time that thesecond signal is received is longer than the second predetermined timeperiod.
 43. The device according to claim 42, wherein the processor isadapted to receive an intervening signal between the first signal andthe second signal of the series of signals, and wherein the length oftime that the intervening signal is received is shorter than the secondpredetermined time period.
 44. The device according to claim 40, whereinthe processor further includes logic to determine whether the vehicle iscontinuing to deviate from the road or whether the vehicle is returningto the road.
 45. The device according to claim 44, wherein the processorfurther includes logic to: initiate a warning to a driver of the vehicleonce the processor has determined that the vehicle is continuing todeviate from the road.
 46. The device according to claim 44, wherein theprocessor is further adapted to issue a vehicle control command once theprocessor has determined that the vehicle is continuing to deviate fromthe road, and wherein the device further includes: a vehicle controlunit in communication with the processor, wherein the vehicle controlunit is adapted to receive the vehicle control command and at least oneof automatically steer the vehicle back onto the road and automaticallybrake the vehicle once the processor has determined that the vehicle iscontinuing to deviate from the road.
 47. The device according to claim40, wherein the processor further includes logic to: determine that thevehicle is contacting a rumble strip if the length of time that the asignal is received is longer than a second predetermined time period.48. A device adapted to determine whether vehicle contact with a roaddeparture warning installation installed on a road should be ignored,comprising: a processor adapted to: receive a signal indicative ofcontact of a rumble strip with a tire of the vehicle; analyze thereceived signal and determine that the rumble strip has contacted thetire; receive input relating to the location of the rumble strip withrespect to a plurality of driving lanes; and receive input that thevehicle is driving on an undivided road and to determine that thevehicle is driving on the undivided road; wherein the processor includeslogic to: issue at least one of a warning command and a vehicle controlcommand when the rumble strip is located within driving lanes and thevehicle is driving on an undivided road.
 49. The device according toclaim 48, wherein the processor receives information based on GPS datato determine that the vehicle is driving on an undivided road.
 50. Thedevice according to claim 48, wherein the processor receives informationbased on a RADAR return to determine that the vehicle is driving on anundivided road.
 51. The device according to claim 48, wherein theprocessor receives information based on a visual sensor return todetermine that the vehicle is driving on an undivided road.